In closed refrigeration and air conditioning systems, the refrigerant and lubricant are normally in contact. Because there is an affinity between lubricants and refrigerants, they are present in refrigeration and air conditioning systems as a mixture of varying composition. The composition will depend upon many factors such as the temperature, whether the system is running or not, whether oil is separated by flow through an oil separator or circuitous path, whether the refrigerant undergoes a phase change, etc. The lubricant in the refrigerant tends to coat the surfaces of the system and deteriorates the heat transfer properties of the system. The refrigerant not only dilutes the lubricant, but is subject to outgassing which results from a pressure reduction and produces a froth which can interfere with lubrication.